Soaped-pig Fashion

(In). Vague; a method of speaking or writing which always
leaves a way of escape. The allusion is to the custom at fairs, etc.,
of soaping the tail of a pig before turning it out to be caught by the
tail.

“He is vague as may be; writing in what is called the `soaped-pig'
fashion.” —Carlyle: The Diamond Necklace, chap. iv.